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What triggered the Younger Dryas cooling?

Asked 26 Oct 2026 by ·4 answers·0·0 following
Most likely: meltwater from the retreating ice sheets weakened the Atlantic overturning circulationAhead on the evidence, not yet confirmed. It needs two reviews to be accepted.

Where it stands

Four answers have been proposed. Meltwater from the retreating ice sheets weakened the Atlantic overturning circulation. leads, with evidence 2 for: supported by its tests. Three are still possible.

Why it matters

The impact hypothesis was offered as the trigger⁠[1]; the standard account places the event in a sequence of deglacial cold spells driven by ocean circulation⁠[2].

Answers 4

Evidence: 2 for
Most likely
Evidence: 1 for, 1 against
Disputed
None of these.
Not tested enough to call either way
Evidence: none yet
Still possible
Evidence: 1 against
Disputed

History

  1. Alley: the GISP2 record shows onset and end within decades, the pattern of circulation switches.For: Meltwater from the retreating ice sheets weakened the Atlantic overturning circulation.
  2. Broecker et al. puts forward: meltwater from the retreating ice sheets weakened the Atlantic overturning circulation.
  3. Broecker et al.: the Younger Dryas resembles other abrupt cold events of the last deglaciation.For: Meltwater from the retreating ice sheets weakened the Atlantic overturning circulation.
  4. Holliday et al.: geomorphic, stratigraphic and fire records show no catastrophic change at the boundary.Against: Impact-driven fires and an impact winter tipped the climate.
  5. Wolbach et al. puts forward: impact-driven fires and an impact winter tipped the climate.
  6. Wolbach et al.: ice-core combustion markers are said to show a biomass-burning episode at the onset.For: Impact-driven fires and an impact winter tipped the climate.
  7. Reinig et al. puts forward: volcanic forcing, from Laacher See or another eruption, pushed a system near a threshold.
  8. Reinig et al.: laacher See erupted about 130 years before the onset, too early to be its direct trigger.Against: Volcanic forcing, from Laacher See or another eruption, pushed a system near a threshold.
  9. Asked on this site
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